Systematic Study Of Two-quasiparticle And Three-quasiparticle Doublet Bands With Configuration ?h_11/2????h_11/2

As a basic symmetry,chiral symmetry,i.e.,chirality is an important phenomenon in nature and the microscopic material world.The chirality in the nucleus is embodied as a chiral doublet bands,i.e.,a pair of?I=1 dipole bands with the same parity,similar energy spectrum and structural properties.Since the prediction of nuclear chirality in 1997 and confirmed it by experiments in 2001,chiral symmetry has become one of the research hot spots in the nuclear structure.At present,more than 60 pairs of chiral bands have been reported in more than 50nuclei in A⁸0,A¹00,A¹30 and A¹90 mass regions.Among them,the A¹30mass region has the most chiral nuclei,forming an obvious island of chiral nuclei.The study of the continuity and boundary of chiral nuclear islands in A¹30 mass region could help to understand the chiral symmetry of nuclei.At the same time,most of the chiral double bands in these chiral candidate nuclei contain configuration components of?h_11/2????h_11/2.This paper summarizes the configuration of all reported candidate chiral bands in A¹30mass region,and systematically studies the experimental characteristics of chiral doublet bands in the odd-odd nuclei in A¹30 mass region,including energy level difference?E,energy oscillation parameter S?I?,and in-band transition probability B?M1?/B?E2?.The common fea-tures of these experimental characteristics and the differences between them are analyzed.And then,The self-consistent tilted axis cranking covariant density functional theory are applied to study the configuration structure of the doublet bands in¹²⁰I on the boundary of the”chiral island”in A¹30 mass region.The high-j proton-particle and neutron-hole configurations favored the doublet bands in¹²⁰I;A systematic comparison is performed,it is found that the energy differences?E for the doublet bands in¹²⁰I and^124-130Cs are very similar.¹²⁴Cs is espe-cially similar to¹²⁰I,i.e.,the energy differences?E is almost the same,which implies¹²⁰I and¹²⁴Cs may have a similar chiral geometry.Furthermore,the experimental features of positive-parity doublet bands in the odd-A cesium isotopes^{125,127,129,131}Cs,including angular momentum alignment,energy staggering,B?M1?/B?E2?etc.are studied systematically and compared to those of the candidate chiral bands in the adjacent odd-odd^124-130Cs.The configuration assign-ments and the dynamics of these bands are discussed.The self-consistent tilted axis cranking covariant density functional theory are performed with configuration reassigned to these bands.The experimental level schemes of four nuclei are well reproduced,and the calculations al-so show four nuclei have obvious triaxial deformations and thus support the candidate chiral doublet bands in^{125,127,129,131}Cs.